Aromatic hydrocarbon formaldehyde resin, modified aromatic hydrocarbon formaldehyde resin and epoxy resin, and method for producing these

ABSTRACT

There is provided an aromatic hydrocarbon formaldehyde resin obtained by reacting an aromatic hydrocarbon compound (A) represented by the following formula (1) with formaldehyde (B) in the presence of an acidic catalyst. 
                         
wherein R represents an organic group having 1 to 10 carbon atoms; l represents an integer of 0 to 2, and m and n represent integers satisfying 1≦m+n≦10, m≧0 and n≧1.

TECHNICAL FIELD

The present invention relates to an aromatic hydrocarbon formaldehyderesin, a modified aromatic hydrocarbon formaldehyde resin and an epoxyresin, and methods for producing these.

BACKGROUND ART

Aromatic hydrocarbon resins, obtained by reacting a polycyclic aromatichydrocarbon having an alkylnaphthalene such as methylnaphthalene and/ora dialkylnaphthalene such as dimethylnaphthalene as main components witha paraformaldehyde in the presence of an aromatic monosulfonic acid, areconventionally well known as resins excellent in the compatibility withepoxy resins and the like and the solubility to organic solvents such asxylene (see Patent Document 1).

There are also well known methods of providing modifieddimethylnaphthalene formaldehyde resins having high heat resistance bymodifying dimethylnaphthalene formaldehyde resins with naphthols,phenols or the like (see Patent Documents 2 and 3).

It is known that under the usual reaction condition of producing sucharomatic hydrocarbon formaldehyde resins, since diarylmethanes formedfrom two molecules of aromatic hydrocarbons and one molecule offormaldehyde are produced, and remain as unreacted components also aftermodification, the mechanical strength and the thermal decompositionresistance of cured products obtained from modified resins decrease.Then, there is made an attempt of suppressing the formation of thediarylmethanes by controlling the reaction condition (see PatentDocument 4).

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 54-86593

Patent Document 2: Japanese Patent Application Laid-Open No. 2009-155638

Patent Document 3: Japanese Patent Application Laid-Open No. 2011-46837

Patent Document 4: Japanese Patent Application Laid-Open No. 61-228013

SUMMARY OF INVENTION Technical Problem

The means described in Patent Document 4, however, is not much more thanone in which the formation of diarylmethanes is suppressed by alteringthe reaction condition including suppression of the reaction rate offormaldehyde, and by which it is difficult to suppress the formation ofthe diarylmethanes more sufficiently than conventionally.

It is an object of the present invention to provide an aromatichydrocarbon formaldehyde resin which allows decreasing, moresufficiently than conventionally, diarylmethanes always ending in beingformed as long as conventionally used reactive substrates are used inproduction of the aromatic hydrocarbon formaldehyde resin, and which isexcellent in the reactivity and the thermal decomposition resistance inmodification, a modified aromatic hydrocarbon formaldehyde resin and anepoxy resin obtained therefrom, and methods for producing these.

Solution to Problem

As a result of exhaustive studies, the present inventors have found thata resin obtained by reacting a specific hydroxymethyl-substitutedaromatic hydrocarbon compound with formaldehyde in the presence of anacidic catalyst can solve the above problem, and this finding has led tothe present invention.

That is, the present invention is as follows.

[1]

An aromatic hydrocarbon formaldehyde resin, being obtained by reactingan aromatic hydrocarbon compound (A) represented by the followingformula (1) with formaldehyde (B) in the presence of an acidic catalyst:

wherein R represents an organic group having 1 to 10 carbon atoms; lrepresents an integer of 0 to 2, and m and n represent integerssatisfying 1≦m+n≦10, m≧0 and n≧1.[2]

The aromatic hydrocarbon formaldehyde resin according to [1], beingobtained by reacting the aromatic hydrocarbon compound (A) withformaldehyde (B) in a molar ratio of (A):(B)=1:1 to 1:20 in the presenceof an acidic catalyst.

[3]

The aromatic hydrocarbon formaldehyde resin according to [¹] or [2],wherein the reaction of the aromatic hydrocarbon compound (A) withformaldehyde (B) is carried out in the presence of an alcohol.

[4]

The aromatic hydrocarbon formaldehyde resin according to any one of [1]to [3], having a weight-average molecular weight of 200 to 25,000.

[5]

The aromatic hydrocarbon formaldehyde resin according to any one of [1]to [4], having an oxygen content of 7 to 18% by mass.

[6]

The aromatic hydrocarbon formaldehyde resin according to any one of [1]to [5], comprising substantially no diarylmethane.

[7]

A method for producing an aromatic hydrocarbon formaldehyde resin,comprising reacting an aromatic hydrocarbon compound (A) represented bythe following formula (1) with formaldehyde (B) in the presence of anacidic catalyst:

wherein R represents an organic group having 1 to 10 carbon atoms; lrepresents an integer of 0 to 2, and m and n represent integerssatisfying 1≦m+n≦10, m≧0 and n≧1.[8]

A modified aromatic hydrocarbon formaldehyde resin, being obtained byreacting an aromatic hydrocarbon formaldehyde resin according to any oneof [1] to [6] with at least one selected from the group consisting ofcompounds represented by the following formulae (2) and (3) in thepresence of an acidic catalyst:

wherein X and Y each independently represent a hydrogen atom or anorganic group having 1 to 10 carbon atoms; and a and b representintegers satisfying 1≦a+b≦10, a≧1 and b≧0, and c represents an integerof 0 to 2.[9]

The modified aromatic hydrocarbon formaldehyde resin according to [8],wherein the compounds represented by the formulae (2) and (3) are atleast one selected from the group consisting of phenol, cresol,catechol, hydroquinone, phenylphenol, biphenol, naphthol,dihydroxynaphthalene, hydroxyanthracene and dihydroxyanthracene.

[10]

A method for producing a modified aromatic hydrocarbon formaldehyderesin, comprising reacting an aromatic hydrocarbon formaldehyde resinaccording to any one of [1] to [6] with at least one selected from thegroup consisting of compounds represented by the following formulae (2)and (3) in the presence of an acidic catalyst:

wherein X and Y each independently represent a hydrogen atom or anorganic group having 1 to 10 carbon atoms; and a and b representintegers satisfying 1≦a+b≦10, a≧1 and b≧0, and c represents an integerof 0 to 2.[11]

An epoxy resin, being obtained by reacting a modified aromatichydrocarbon formaldehyde resin according to [8] with epichlorohydrin.

[12]

A method for producing an epoxy resin, comprising reacting a modifiedaromatic hydrocarbon formaldehyde resin according to [8] withepichlorohydrin to thereby obtain the epoxy resin.

Advantageous Effects of Invention

The present invention can provide an aromatic hydrocarbon formaldehyderesin which allows decreasing, more sufficiently than conventionally,diarylmethanes always ending in being formed as long as conventionallyused reactive substrates are used in production of the aromatichydrocarbon formaldehyde resin, and which is excellent in the reactivityand the thermal decomposition resistance in modification, a modifiedaromatic hydrocarbon formaldehyde resin and an epoxy resin obtainedtherefrom, and methods for producing these.

DESCRIPTION OF EMBODIMENT

Hereinafter, an embodiment according to the present invention will bedescribed (hereinafter, referred to as “the present embodiment”). Here,the present embodiment is an exemplification to describe the presentinvention, and the present invention is not limited only to the presentembodiment.

<Aromatic Hydrocarbon Formaldehyde Resin>

An aromatic hydrocarbon formaldehyde resin according to the presentembodiment is obtained by condensation reacting an aromatic hydrocarboncompound (hereinafter, also referred to as “hydroxymethyl-substitutedaromatic hydrocarbon compound”) represented by the following formula (1)with formaldehyde in the presence of an acidic catalyst.

Here, a mechanism of producing a diarylmethane in a conventionalproduction process of an aromatic hydrocarbon formaldehyde resin isshown below by taking a reaction of metaxylene as an example.

In the mechanism, first, formaldehyde is reacted with xylene to therebyproduce xylenemethanol; and the xylenemethanol is subjected to adehydrating condensation reaction with another molecule of xylene tothereby produce the diarylmethane represented by the above formula (4).

By contrast, in the present embodiment, since ahydroxymethyl-substituted aromatic hydrocarbon compound as a rawmaterial has a structure in which one hydroxymethyl group is previouslybonded, even when these compounds are subjected to a dehydratingcondensation reaction, a compound represented by the following formula(5) which is crosslinked with a methyleneoxymethylene group is obtained,so diarylmethanes can be decreased more sufficiently thanconventionally.

A major reaction product as an aromatic hydrocarbon formaldehyde resinobtained by using a reactive substrate according to the presentembodiment has a structure containing hydroxymethyl groups previouslybonded to the aromatic rings, and methylene groups and oxymethylenegroups formed from added formaldehyde. The major reaction product isobtained as a mixture of a plurality of compounds in which bondingpositions and numbers of these substituents on the aromatic rings aredifferent. More specifically, for example, a naphthalene formaldehyderesin obtained by reacting naphthalenemethanol in the presence offormalin and concentrated sulfuric acid may be a mixture whoserepresentative composition has compounds represented by the followingformulae (6), (7), (8) and (9).

An aromatic hydrocarbon compound represented by the following formula(1) according to the present embodiment is a compound in which at leastone hydrogen atom on a benzene ring, a naphthalene ring or an anthracenering is substituted with a hydroxymethyl group. Examples of such acompound include phenylmethanol, phenyldimethanol, tolylmethanol,tolyldimethanol, xylylmethanol such as 2,4-dimethylbenzyl alcohol,xylyldimethanol, mesitylmethanol, mesityldimethanol, naphthylmethanolsuch as 1-naphthalenemethanol and 2-naphthalenemethanol,naphthyldimethanol, methylnaphthylmethanol, methylnaphthyldimethanol,dimethylnaphthylmethanol, dimethylnaphthyldimethanol,anthracenylmethanol, anthracenyldimethanol, methylanthracenylmethanol,and methylanthracenyldimethanol.

These hydroxymethyl-substituted aromatic hydrocarbon compounds are notparticularly limited, and industrially available ones can be utilized.

wherein R represents an organic group having 1 to 10 carbon atoms; and lrepresents an integer of 0 to 2, and m and n represent integerssatisfying 1≦m+n≦10, m≧0 and n≧1.

In the formula (1), from the viewpoint of the productivity, R ispreferably an alkyl group having 1 to 10 carbon atoms or an allyl grouphaving 3 to 10 carbon atoms, and more preferably an alkyl group having 1to 4 carbon atoms or an allyl group having 3 to 6 carbon atoms; and itis preferable that l is 0 to 2, m is 0 to 2, and n is 1 to 2. Examplesof such an alkyl group and allyl group include a methyl group, an ethylgroup, a propyl group, a butyl group, a pentyl group, a hexyl group, aheptyl group, an octyl group, a nonyl group, a decyl group, a propenylgroup, a butenyl group, a pentenyl group, a hexenyl group, a heptenylgroup, an octenyl group, a nonenyl group and a decenyl group. Furtherthe compound represented by the above formula (1) is more preferablyanthracenylmethanol, xylylmethanol or naphthylmethanol, and particularlypreferably xylylmethanol or naphthylmethanol.

Formaldehyde in the present embodiment is not particularly limited, andmay be used, for example, in a form of a formaldehyde aqueous solution,which is usually industrially available. Formaldehyde in the presentembodiment includes formaldehyde generated in use of a compound such asparaformaldehyde or trioxane, which generates formaldehyde. Among these,from the viewpoint of the suppression of gelation, preferable is aformaldehyde aqueous solution.

In the condensation reaction in the present embodiment, the molar ratioof the compound represented by the above formula (1) to formaldehyde (acompound represented by the above formula (1): formaldehyde) is notparticularly limited, but is preferably 1:1 to 1:20, more preferably1:1.5 to 1:17.5, still more preferably 1:2 to 1:15, further still morepreferably 1:2 to 1:12.5, further still more preferably 1:2.5 to 1:10,particularly preferably 1:3 to 1:10, and extremely preferably 1:3 to1:5. The aromatic hydrocarbon formaldehyde resin according to thepresent embodiment can have more of a crosslinking structure bycondensation reacting a compound represented by the above formula (1)with formaldehyde in the above-mentioned proportions. Further bycondensation reacting a compound represented by the above formula (1)with formaldehyde in the above-mentioned proportions, the amount of thehydroxymethyl-substituted aromatic hydrocarbon compound remaining as anunreacted substance can be made smaller, and the yield of the obtainedaromatic hydrocarbon formaldehyde resin can be maintained higher.

The acidic catalyst in the present embodiment is not particularlylimited, and well-known inorganic acids and organic acids can be used.Examples of the acidic catalyst include inorganic acids such ashydrochloric acid, sulfuric acid, phosphoric acid, hydrobromic acid andhydrofluoric acid; organic acids such as oxalic acid, malonic acid,succinic acid, adipic acid, sebacic acid, citric acid, fumaric acid,maleic acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid,trifluoroacetic acid, dichloroacetic acid, trichloroacetic acid,trifluoromethanesulfonic acid, benzenesulfonic acid, naphthalenesulfonicacid and naphthalenedisulfonic acid; Lewis acids such as zinc chloride,aluminum chloride, iron chloride and boron trifluoride; and solid acidssuch as silicotungstic acid, phosphotungstic acid, silicomolybdic acidand phosphomolybdic acid.

Among these, from the viewpoint of the productivity, preferable aresulfuric acid, oxalic acid, citric acid, p-toluenesulfonic acid,methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonicacid, naphthalenesulfonic acid, naphthalenedisulfonic acid andphosphotungstic acid. The acidic catalyst is used singly or incombinations of two or more.

The amount of an acidic catalyst used is not particularly limited, butis, based on 100 parts by mass of the total amount of a compoundrepresented by the above formula (1) and formaldehyde, preferably 0.0001to 100 parts by mass, more preferably 0.001 to 85 parts by mass, andstill more preferably 0.001 to 70 parts by mass. By making the amount ofan acidic catalyst used in such a range, a more proper reaction rate canbe achieved and an increase in the resin viscosity due to the highreaction rate can be prevented more effectively.

A method of adding an acidic catalyst to a reaction system is notparticularly limited, and the acidic catalyst may be added collectivelyor dividedly.

The pressure of the condensation reaction in the present embodiment isnot particularly limited, and may be normal pressure or a pressurizedpressure, that is, a pressure higher than normal pressure.

A method of the condensation reaction in the present embodiment is notparticularly limited, and an example thereof includes a method ofcarrying out the condensation reaction while raw materials to be usedand an acidic catalyst are heated to reflux at a temperature or higher(for example, usually 80 to 300° C.) at which the raw materials becomecompatible with one another, or produced water is distilled away, undernormal pressure. In the condensation reaction in the present embodiment,as required, an inert gas such as nitrogen, helium or argon may bepassed in the reaction system.

In the condensation reaction in the present embodiment, as required, asolvent inactive to the condensation reaction may be used. Examples ofsuch a solvent include aromatic hydrocarbons such as toluene,ethylbenzene and xylene; saturated aliphatic hydrocarbons such asheptane and hexane; cycloaliphatic hydrocarbons such as cyclohexane;ethers such as dioxane and dibutyl ether; alcohols such as 2-propanol;ketones such as methyl isobutyl ketone; carboxylate esters such as ethylpropionate; and carboxylic acids such as acetic acid. The solventinactive to the condensation reaction is used singly or in combinationsof two or more.

The condensation reaction in the present embodiment is not particularlylimited, but is preferably carried out in the presence of an alcohol.When an alcohol is present, the terminals of the resin are sealed withthe alcohol, and the aromatic hydrocarbon formaldehyde resin having alower molecular weight and a lower dispersion (that is, the molecularweight distribution is narrower, further in other words, the value ofthe weight-average molecular weight/number-average molecular weight(Mw/Mn) is smaller) can be obtained. As a result, the aromatichydrocarbon formaldehyde resin according to the present embodiment is aresin better in the solvent solubility and low in the melt viscosityalso after modification. The alcohol is not particularly limited, andexamples thereof include monools having 1 to 12 carbon atoms and diolshaving 1 to 12 carbon atoms. The alcohol may be used singly or incombinations of two or more. Among these, from the viewpoint of theproductivity of the aromatic hydrocarbon formaldehyde resin, preferableare propanol, butanol, octanol and 2-ethylhexanol.

In the case where an alcohol is present, the amount of the alcohol addedis not particularly limited, but is preferably, for example, such anamount that the hydroxyl group of the alcohol is 1 to 10 equivalentsbased on 1 equivalent of hydroxymethyl groups in a compound representedby the above formula (1).

In the condensation reaction in the present embodiment, ahydroxymethyl-substituted aromatic hydrocarbon compound, formaldehydeand an acidic catalyst may be added simultaneously to a reaction system,or a hydroxymethyl-substituted aromatic hydrocarbon compound may besuccessively added to a system in which formaldehyde and an acidiccatalyst are present. The successive addition method is preferable fromthe viewpoint that the oxygen content in an obtained aromatichydrocarbon formaldehyde resin can be increased, and in the case wherethe resin is modified later (hereinafter, this step of the modificationis referred to as “modification step”), the resin can be reacted morewith compounds represented by the following formulae (2) and (3).

The reaction time of the condensation reaction is not particularlylimited, but is preferably 0.5 to 30 hours, more preferably 0.5 to 20hours, and still more preferably 0.5 to 10 hours. By adjusting thereaction time in such a range, an aromatic hydrocarbon formaldehyderesin excellent in the thermal decomposition resistance can be obtainedmore economically and industrially more advantageously.

The reaction temperature of the condensation reaction is notparticularly limited, but is preferably 80 to 300° C., more preferably85 to 270° C., and still more preferably 90 to 240° C. By adjusting thereaction temperature in such a range, an aromatic hydrocarbonformaldehyde resin can be obtained more economically and industriallymore advantageously.

After the termination of the reaction, as required, the solvent inactiveto the condensation reaction is further added in and dilutes the system;and thereafter, the system is allowed to stand still to be therebyseparated into two phases. Then, a water phase is removed and a resinphase being an oil phase is obtained; and the resin phase is washed withwater to sufficiently remove the acidic catalyst from the resin phase.Thereafter, the added solvent and the unreacted raw materials areremoved from the resin phase by a usual method such as distillation tothereby obtain an aromatic hydrocarbon formaldehyde resin according tothe present embodiment.

The aromatic hydrocarbon formaldehyde resin to be obtained by the abovereaction, from the viewpoint of the balance of the oxygen content andthe heat resistance, preferably has a structure in which at least partof aromatic rings is crosslinked with a bond represented by thefollowing formula (i) and/or a bond represented by the following formula(ii).—(CH₂)_(p)—  (i)—CH₂-A-  (ii)wherein in the formula (i), p represents an integer of 1 to 10; and inthe formula (ii), A represents a divalent group represented by(OCH₂)_(m), and m represents an integer of 1 to 10.

In this preferred embodiment, at least part of aromatic rings may becrosslinked with a bond in which a bond represented by —(CH₂)_(p)— and abond represented by —(OCH₂)_(m)— are randomly sequenced, for example,—CH₂—OCH₂—CH₂—, —(CH₂)₂—OCH₂—, and —CH₂—OCH₂—OCH₂—CH₂—.

In the aromatic hydrocarbon formaldehyde resin according to the presentembodiment, from the viewpoint of the thermal decomposition resistanceand the solubility to the solvent, the number-average molecular weight(Mn) in terms of polystyrene as measured by gel permeationchromatography (hereinafter, represented as “GPC”) analysis is, notparticularly limited, but preferably 200 to 4,000, more preferably 250to 3,500, and still more preferably 300 to 4,000.

In the aromatic hydrocarbon formaldehyde resin according to the presentembodiment, from the viewpoint of the thermal decomposition resistanceand the solubility to the solvent, the weight-average molecular weight(Mw) in terms of polystyrene as measured by GPC is, not particularlylimited, but preferably 200 to 25,000, more preferably 250 to 20,000,and still more preferably 300 to 15,000.

In the aromatic hydrocarbon formaldehyde resin according to the presentembodiment, from the viewpoint of the thermal decomposition resistanceand the melt viscosity, the degree of dispersion (Mw/Mn) is, notparticularly limited, but preferably 1.0 to 5.0, more preferably 1.1 to4.5, and still more preferably 1.2 to 4.0.

In the aromatic hydrocarbon formaldehyde resin according to the presentembodiment, from the viewpoint of the thermal decomposition resistance,and the reactivity with compounds represented by the following formulae(2) and (3) in a modification step described later, the oxygen contentis, not particularly limited, but preferably 7 to 18% by mass, morepreferably 7 to 17% by mass, and still more preferably 8 to 17% by mass.Since the reactivity of a modification reaction in the modification stepdescribed later is increased in proportion to the oxygen content in theresin, by adjusting the oxygen content in such a range, the compoundsrepresented by the following formulae (2) and (3) can be more reacted.Here, the oxygen content in the resin is measured by an organicelemental analysis.

In the aromatic hydrocarbon formaldehyde resin according to the presentembodiment, from the viewpoint of the thermal decomposition resistanceand the handling, the resin is, not particularly limited, but preferablyliquid at normal temperature (25° C.). From the same viewpoint, thesoftening point of the aromatic hydrocarbon formaldehyde resin ispreferably 140° C. or lower, more preferably 130° C. or lower, and stillmore preferably 120° C. or lower. Here, the lower limit of the softeningpoint is not particularly limited. In the present description, thesoftening point is measured according to a method described in Examples.

In the aromatic hydrocarbon formaldehyde resin according to the presentembodiment, from the viewpoint of the thermal decomposition resistanceand the solubility to the solvent, the hydroxyl value is, notparticularly limited, but preferably 0 to 100 mgKOH/g, more preferably 5to 95 mgKOH/g, and still more preferably 10 to 90 mgKOH/g. In thepresent description, the hydroxyl value is measured according to amethod described in Examples.

The aromatic hydrocarbon formaldehyde resin according to the presentembodiment preferably contains substantially no diarylmethane. Here,“contains substantially no diarylmethane” means that in GPC analysisaccording to a method described in Examples described later, no peaks ofdiarylmethanes are detected.

<Modified Aromatic Hydrocarbon Formaldehyde Resin>

A modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment is obtained by heating and reacting the abovearomatic hydrocarbon formaldehyde resin according to the presentembodiment with at least one selected from the group consisting ofcompounds represented by the following formula (2) and (3) in thepresence of an acidic catalyst.

In the present embodiment, this reaction is referred to as “modificationreaction”.

wherein X and Y each independently represent a hydrogen atom or anorganic group having 1 to 10 carbon atoms; and a and b representintegers satisfying 1≦a+b≦10, a≧1 and b≧0, and c represents an integerof 0 to 2. The compound represented by the above formula (2) is usedsingly or in combinations of two or more.

In the above formula (2), from the viewpoint of the productivity, X andY are each independently preferably a hydrogen atom, an alkyl grouphaving 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms,or a cyclohexyl group, and more preferably a hydrogen atom, an alkylgroup having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbonatoms, or a cyclohexyl group; and it is preferable that a and b are eachindependently 1 to 2, and c is 0 to 2. Further from the viewpoint ofeasily providing an epoxy resin described later, X is still morepreferably a hydrogen atom.

Specific examples of the compound represented by the above formula (2)include phenol, methoxyphenol, benzoxyphenol, catechol, resorcinol,hydroquinone, cresol, phenylphenol, naphthol, methoxynaphthol,benzoxynaphthol, di hydroxynaphthalene, hydroxyanthracene,methoxyanthracene, benzoxyanthracene and dihydroxyanthracene. Amongthese, from the viewpoint of easy availability, preferable are phenol,cresol, catechol, hydroquinone, phenylphenol, naphthol,dihydroxynaphthalene, hydroxyanthracene and dihydroxyanthracene, andmore preferable are phenol and naphthol.

Further as the compound represented by the above formula (2), from theviewpoint of being excellent in the thermal decomposition resistance,more preferable phenol derivatives are phenol, phenylphenol, naphthol,methoxynaphthol, benzoxynaphthol, dihydroxynaphthalene,hydroxyanthracene, methoxyanthracene, benzoxyanthracene anddihydroxyanthracene.

Further among these, those having a hydroxy group are, since beingexcellent in crosslinkability with an acid crosslinking agent, stillmore preferable; and particularly preferable are phenol, phenylphenol,naphthol, dihydroxynaphthalene, hydroxyanthracene anddihydroxyanthracene.

In the above formula (3), from the viewpoint of the productivity, X andY are each independently preferably a hydrogen atom, an alkyl grouphaving 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms,or a cyclohexyl group, and more preferably a hydrogen atom, an alkylgroup having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbonatoms, or a cyclohexyl group; and it is preferable that a and b are eachindependently 1 to 2, and c is 0 to 2. Further from the viewpoint ofeasily providing an epoxy resin described later, X is still morepreferably a hydrogen atom.

Specific examples of the compound represented by the above formula (3)include biphenol, methoxybiphenol and benzoxybiphenol. Among these, fromthe viewpoint of being easy availability, biphenol is preferable.

The amount of the compounds used represented by the above formulae (2)and (3) is, based on 1 mol of oxygen atoms of the aromatic hydrocarbonformaldehyde resin, preferably 0.1 to 5 mol, more preferably 0.2 to 4mol, and still more preferably 0.3 to 3 mol. By adjusting the amount ofthe compounds used represented by the above formulae (2) and (3) in sucha range, the yield of an obtained modified aromatic hydrocarbonformaldehyde resin can be maintained higher, and the amount of thecompounds represented by the above formulae (2) and (3) which remain asunreacted substances can be made smaller.

The molecular weight of the modified aromatic hydrocarbon formaldehyderesin receives the influences of the number of moles of oxygen atoms(hereinafter, referred to as “the number of moles of oxygen contained”)of the aromatic hydrocarbon formaldehyde resin and of the amount of thecompounds used represented by the above formulae (2) and (3). When theboth of them increase, the molecular weight of the modified aromatichydrocarbon formaldehyde resin reduces.

Here, the number of moles of oxygen contained can be calculated bymeasuring an oxygen content (% by mass) in the aromatic hydrocarbonformaldehyde resin by an organic elemental analysis and according to thefollowing calculation expression.Number of moles of oxygen contained (mol)=amount of the aromatichydrocarbon formaldehyde resin (g) used×oxygen content (% by mass)/16

The acidic catalyst usable in the above modification reaction in thepresent embodiment is not particularly limited, and can suitably beselected from well-known inorganic acids and organic acids. Examples ofthe acidic catalyst include inorganic acids such as hydrochloric acid,sulfuric acid, phosphoric acid, hydrobromic acid and hydrofluoric acid;organic acids such as oxalic acid, malonic acid, succinic acid, adipicacid, sebacic acid, citric acid, fumaric acid, maleic acid, formic acid,p-toluenesulfonic acid, methanesulfonic acid, trifluoroacetic acid,dichloroacetic acid, trichloroacetic acid, trifluoromethanesulfonicacid, benzenesulfonic acid, naphthalenesulfonic acid andnaphthalenedisulfonic acid; Lewis acids such as zinc chloride, aluminumchloride, iron chloride and boron trifluoride, and solid acids such assilicotungstic acid, phosphotungstic acid, silicomolybdic acid andphosphomolybdic acid. Among these, from the viewpoint of theenvironmental problem and the productivity, preferable are sulfuricacid, oxalic acid, citric acid, p-toluenesulfonic acid, methanesulfonicacid, trifluoromethanesulfonic acid, benzenesulfonic acid,naphthalenesulfonic acid, naphthalenedisulfonic acid and phosphotungsticacid. The acidic catalyst is used singly or in combinations of two ormore.

The amount of the acidic catalyst used is not particularly limited, butis, based on 100 parts by mass of the aromatic hydrocarbon formaldehyderesin, preferably 0.0001 to 100 parts by mass, more preferably 0.001 to85 parts by mass, and still more preferably 0.001 to 70 parts by mass.By adjusting the amount of the acidic catalyst used in such a range, amore proper reaction rate can be achieved, and an increase in the resinviscosity due to the high reaction rate can be prevented moreeffectively. The acidic catalyst may be placed collectively or dividedlyin a reaction system.

A method of the above modification reaction in the present embodiment isnot particularly limited. The method, for example, involves that themodification reaction is carried out while raw materials to be used andan acidic catalyst are heated to reflux at a temperature or higher (forexample, usually 80 to 300° C.) at which the raw materials becomecompatible with one another, or produced water is distilled away, in thepresence of an acidic catalyst and at normal pressure. The pressure inthe modification reaction may be normal pressure, or may be apressurized pressure, that is, a pressure higher than normal pressure.In the modification reaction, as required, an inert gas such asnitrogen, helium or argon may be passed in a reaction system.

In the modification reaction in the present embodiment, as required, asolvent inactive to the condensation reaction may be used. Examples ofsuch a solvent include aromatic hydrocarbons such as toluene,ethylbenzene and xylene; saturated aliphatic hydrocarbons such asheptane and hexane; cycloaliphatic hydrocarbons such as cyclohexane;ethers such as dioxane and dibutyl ether; alcohols such as 2-propanol;ketones such as methyl isobutyl ketone; carboxylate esters such as ethylpropionate; and carboxylic acids such as acetic acid. The solventinactive to the condensation reaction is used singly or in combinationsof two or more.

The reaction time of the modification reaction in the present embodimentis not particularly limited, but is preferably 0.5 to 20 hours, morepreferably 1 to 15 hours, and still more preferably 2 to 10 hours. Byadjusting the reaction time in such a range, a modified aromatichydrocarbon formaldehyde resin excellent in the thermal decompositionresistance and the solubility to the solvent can be obtained moreeconomically and industrially more advantageously.

The reaction temperature of the modification reaction in the presentembodiment is not particularly limited, but is preferably 80 to 300° C.,more preferably 85 to 270° C., and still more preferably 90 to 240° C.By adjusting the reaction temperature in such a range, a modifiedaromatic hydrocarbon formaldehyde resin excellent in the thermaldecomposition resistance can be obtained more economically andindustrially more advantageously.

After the termination of the modification reaction, as required, thesolvent inactive to the condensation reaction is further added in anddilutes the system; and thereafter, the system is allowed to stand stillto be thereby separated into two phases. Then, a water phase is removedand a resin phase being an oil phase is obtained; further, the resinphase is washed with water to sufficiently remove the acidic catalystfrom the resin phase. Thereafter, the added solvent and the unreactedraw materials are removed from the resin phase by a usual method such asdistillation to thereby obtain a modified aromatic hydrocarbonformaldehyde resin according to the present embodiment.

In the modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment, as compared with the aromatic hydrocarbonformaldehyde resin before the modification, the thermal decompositionresistance (thermogravimetric loss rate) and the hydroxyl value areraised. For example, when the modification is carried out under theconditions of an amount of the acidic catalyst used of 0.05 parts bymass, a reaction time of 5 hours, and a reaction temperature of 200° C.,the thermal decomposition resistance (thermogravimetric loss rate) isincreased by about 1 to 50%, and the hydroxyl value is increased byabout 1 to 300 mgKOH/g. Here, the “thermogravimetric loss rate” ismeasured according to a method described in Examples.

In the modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment, from the viewpoint of the thermal decompositionresistance and the solubility to the solvent, the number-averagemolecular weight (Mn) in terms of polystyrene as measured by GPCanalysis is, not particularly limited, but preferably 200 to 4,000, morepreferably 250 to 3,500, and still more preferably 300 to 3,000.

In the modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment, from the viewpoint of the thermal decompositionresistance and the solubility to the solvent, the weight-averagemolecular weight (Mw) in terms of polystyrene as measured by GPCanalysis is, not particularly limited, but preferably 200 to 25,000,more preferably 250 to 20,000, and still more preferably 300 to 150,000.

In the modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment, from the viewpoint of the thermal decompositionresistance and the solubility to the solvent, the degree of dispersion(Mw/Mn) is, not particularly limited, but preferably 1.0 to 5.0, morepreferably 1.1 to 4.5, and still more preferably 1.2 to 4.0.

In the modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment, from the viewpoint of the thermal decompositionresistance and the handling, the softening point is, not particularlylimited, but preferably 50° C. to 240° C., more preferably 60 to 230°C., and still more preferably 70 to 220° C.

In the modified aromatic hydrocarbon formaldehyde resin according to thepresent embodiment, from the viewpoint of the thermal decompositionresistance and the solubility to the solvent, the hydroxyl value is, notparticularly limited, but preferably 60 to 380 mgKOH/g, more preferably70 to 370 mgKOH/g, and still more preferably 80 to 360 mgKOH/g.

<Epoxy Resin>

An epoxy resin according to the present embodiment is obtained byreacting the modified aromatic hydrocarbon formaldehyde resin withepichlorohydrin. The amount of epichlorohydrin used is, based on 1 molof hydroxyl groups of the modified aromatic hydrocarbon formaldehyderesin, preferably 0.8 to 2 mol, and more preferably 0.9 to 1.2 mol. Byadjusting the amount of epichlorohydrin used in such a range, the yieldof an obtained epoxy resin can be maintained higher.

The reaction of the modified aromatic hydrocarbon formaldehyde resinwith epichlorohydrin is carried out in the presence of an alkaline metalhydroxide. The alkaline metal hydroxide is not particularly limited, andexamples thereof include sodium hydroxide and potassium hydroxide. Amongthese, from the viewpoint of the economic efficiency, sodium hydroxideis preferable. The alkaline metal hydroxide is used singly or incombinations of two or more.

The amount of the alkaline metal hydroxide used is not particularlylimited, but is, based on 100 parts by mass of the modified aromatichydrocarbon formaldehyde resin, preferably 10 to 150 parts by mass, andmore preferably 20 to 100 parts by mass. By adjusting the amount of thealkaline metal hydroxide used in such a range, the effect of completingthe ring-closure reaction can be achieved. The alkaline metal hydroxidemay be placed collectively or dividedly in a reaction system.

A method of the reaction of the modified aromatic hydrocarbonformaldehyde resin with epichlorohydrin in the present embodiment is notparticularly limited, but an example thereof includes a method in whicha resin is dissolved in an excessive amount of epichlorohydrin, andthereafter, the reaction is carried out in the presence of an alkalinemetal hydroxide such as sodium hydroxide at 60 to 120° C. for 1 to 10hours.

In the reaction of the modified aromatic hydrocarbon formaldehyde resinaccording to the present embodiment with epichlorohydrin, as required, asolvent inactive to the reaction may be used. Examples of such a solventinclude hydrocarbons such as heptane and toluene, and alcohols such asethanol, propanol and butanol. These solvents are used singly or incombinations of two or more.

The reaction time of the modification reaction in the present embodimentis not particularly limited, but is preferably 0.5 to 20 hours, morepreferably 1 to 15 hours, and still more preferably 2 to 10 hours. Byadjusting the reaction time in such a range, a modified aromatichydrocarbon formaldehyde resin excellent in the thermal decompositionresistance and the solubility to the solvent can be obtained moreeconomically and industrially more advantageously.

The reaction temperature of the reaction of the modified aromatichydrocarbon formaldehyde resin with epichlorohydrin in the presentembodiment is not particularly limited, but is preferably 50 to 150° C.,and more preferably 60 to 120° C. By adjusting the reaction temperaturein such a range, an epoxy resin can be obtained more economically andindustrially more advantageously.

The epoxy resin according to the present embodiment is not particularlylimited, but is, from the viewpoint of the reactivity, preferably onecontaining at least one selected from the group consisting of structuresrepresented by the following formulae (11) and (12).

wherein Y is the same in the above formula (2); Z represents a glycidylgroup, an aryl group having 6 to 10 carbon atoms or a cyclohexyl group;and a and b represent integers satisfying 1≦a+b≦10, a≧1 and b≧0, and crepresents an integer of 0 to 2.

In the epoxy resin according to the present embodiment, the epoxyequivalent is, not particularly limited, but preferably 150 to 1,000g/eq, and more preferably 200 to 500 g/eq. By adjusting the epoxyequivalent in the above range, the effect of well balancing the moistureabsorption rate and the curability tends to be more effectivelyachieved. The epoxy equivalent is measured according to a methoddescribed in following Examples.

In the epoxy resin according to the present embodiment, the content of ahydrolyzable halogen, which may cause corrosion of wiring, can be morereduced. Specifically, the content of the hydrolyzable halogen containedin the epoxy resin according to the present invention is, based on 100parts by mass of the epoxy resin, preferably 2,000 ppm or lower, morepreferably 1,000 ppm or lower, and still more preferably 750 ppm orlower. The content of the hydrolyzable halogen is measured according toa method described in following Examples.

The aromatic hydrocarbon formaldehyde resin according to the presentembodiment is, since being one in which diarylmethanes formed from twomolecules of aromatic hydrocarbons and one molecule of formaldehyde aresufficiently decreased, excellent in the reactivity in the modificationand the thermal decomposition resistance. Therefore, the modifiedaromatic hydrocarbon formaldehyde resin obtained by modifying thearomatic hydrocarbon formaldehyde resin is capable of being utilized inbroad applications including electric insulating materials, resistresins, semiconductor sealing resins, printed wiring board adhesives,matrix resins for electric laminated plates mounted on electric devices,electronic devices, industrial devices and the like, build-up laminatedplate materials, fiber-reinforced plastic resins, sealing resins forliquid crystal display panels, coating materials, various types ofcoating agents, adhesives, coating agents for semiconductors and resistresins in the semiconductor production.

EXAMPLES

Hereinafter, the present invention will be described in more detail, butthe present invention is not limited to these Examples.

<Molecular Weight>

The weight-average molecular weight (Mw) and the number-averagemolecular weight (Mn) in terms of polystyrene were determined by GPCanalysis, and the degree of dispersion (Mw/Mn) was determined therefrom.The apparatus and the analysis condition used in the analysis were asfollows.

Apparatus: Shodex GPC-101 (manufactured by Showa Denko K.K., productname)

Column: LF-804×3

Eluate: THF 1 mL/min

Temperature: 40° C.

<Presence Ratio of the Diarylmethane in the Resin>

The presence ratio of the diarylmethane was calculated using thefollowing calculation expression from values acquired from GPC analysis.an integrated value of the peak of the diarylmethane/an integrated valueof the peaks of the whole resin×100(%)  Calculation expression:<Contents of Carbon and Oxygen in the Resin>

The contents (% by mass) of carbon and oxygen in the resin were measuredby an organic elemental analysis. Further the number of moles of oxygencontained per g of the resin was calculated according to the followingcalculation expression. An apparatus used in the analysis was asfollows.

Apparatus: CHN Corder MT-6 (manufactured by Yanako Bunseki Kogyo KK,product name)number of moles of oxygen contained per g of the resin (mol/g)=oxygencontent (% by mass)/16  Calculation expression:<Softening Point>

The softening point of the resin was measured according to JIS K5601.

<Hydroxyl Value>

The hydroxyl value was measured according to JIS K1557.

<Thermogravimetric Loss Rate>

A weight loss rate from 200° C. to 350° C. was measured during heating asample at 10° C./min in a nitrogen circulation of 300 mL/min. Anapparatus used in the measurement was as follows.

Apparatus: EXSTAR6000 TG/DTA6200 (manufactured by SII, product name)

<Epoxy Equivalent>

The epoxy equivalent was measured according to JIS K7236.

<Content of the Hydrolyzable Halogen>

1.0 g of a sample was weighed in a beaker; and 30 mL of dioxane wasadded and the sample was completely dissolved. 5 mL of a 1N alcoholicKOH was added thereto by a whole pipette; thereafter, a cooling tube isattached to the beaker, and boiling reflux was carried out in an oilbath for 30 minutes. The 1N alcoholic KOH was beforehand prepared byweighing 56.1 g of potassium hydroxide in a 1-L messflask and dissolvingit in a 95.0% ethanol. Thereafter, the beaker is cooled, and 5 mL ofmethanol and 100 mL of 80% acetone-water solution were added. Then, astirrer bar was put in the beaker; 2 mL of nitric acid was added; andthe solution was titrated with a 0.01N silver nitrate reference solutionby a potentiometric titration apparatus. The content of the hydrolyzablehalogen in the sample was calculated by the following expression.A content of the hydrolyzable halogen (ppm)=((A−B)×35.5×N×F×1000)/Wwherein A: an amount (mL) of the 0.01N silver nitrate reference solutiontaken for the titration of the sample, B: an amount (mL) of the 0.01Nsilver nitrate reference solution taken for the titration in a blanktest, N: a normality of the silver nitrate reference solution, F: atiter of the silver nitrate reference solution, and W: a sample weight(g).

Example 1

(Xylenemethanol Formaldehyde Resin)

97.3 g of a 37% by mass of formalin aqueous solution (1.2 mol asformaldehyde, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and108.6 g of a 98% by mass of sulfuric acid (manufactured by MitsubishiGas Chemical Co., Ltd.) were placed in a 1 L-internal volume four-neckflask having an outlet at the bottom equipped with a Dimroth condenser,a thermometer and a stirring blade in a nitrogen gas flow. 81.7 g of amelted 2,4-dimethylbenzyl alcohol (0.6 mol, manufactured by MitsubishiGas Chemical Co., Ltd.) was dropped thereto over 2 hours at normalpressure at about 100° C. under reflux and stirring, and thereafterallowed to react further for 2 hours. Then, 100 g of ethylbenzene(manufactured by Wako Pure Chemical Industries, Ltd.) and 100 g ofmethyl isobutyl ketone (Wako Pure Chemical Industries, Ltd.) as dilutingsolvents were added thereto, and allowed to stand still; thereafter, anoil phase as a separated upper phase was left and a water phase as alower phase was removed. Further, the oil phase was neutralized andwashed with water; and ethylbenzene and methyl isobutyl ketone weredistilled away under reduced pressure to thereby obtain 86.3 g of acolorless xylenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 540; Mw was1,090; and Mw/Mn was 2.02. Further as a result of an organic elementalanalysis of the resin, the carbon content was 75.3% by mass; and theoxygen content was 14.6% by mass (the number of moles of oxygencontained per g of the resin was 0.0091 mol/g). Further the hydroxylvalue of the resin was 45 mgKOH/g. Here, in the resin, no dixylylmethanewas detected.

Example 2

(Naphthalenemethanol Formaldehyde Resin)

94.8 g of 1-naphthalenemethanol (0.6 mol, manufactured by Tokyo ChemicalIndustrial Co., Ltd.), 219 g of a 37% by mass of formalin aqueoussolution (2.7 mol as formaldehyde, manufactured by Mitsubishi GasChemical Co., Ltd.) and 108.6 g of a 98% by mass of sulfuric acid(manufactured by Mitsubishi Gas Chemical Co., Ltd.) were placed in a 1L-internal volume four-neck flask having an outlet at the bottomequipped with a Dimroth condenser, a thermometer and a stirring blade ina nitrogen gas flow. The solution was allowed to react at normalpressure at about 100° C. for 5 hours under reflux and stirring. 300 gof ethylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.)and 200 g of methyl isobutyl ketone (Wako Pure Chemical Industries,Ltd.) as diluting solvents were added thereto, and allowed to standstill; thereafter, an oil phase as a separated upper phase was left anda water phase as a lower phase was removed. Further the oil phase wasneutralized and washed with water; and ethylbenzene and methyl isobutylketone were distilled away under reduced pressure to thereby obtain 93.4g of a light yellow solid naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 604; Mw was1,126; and Mw/Mn was 1.87. Further as a result of an organic elementalanalysis of the resin, the carbon content was 82.3% by mass; and theoxygen content was 11.6% by mass (the number of moles of oxygencontained per g of the resin was 0.0073 mol/g). Further the softeningpoint of the resin was 79° C.; and the hydroxyl value thereof was 33mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Example 3

(Naphthalenemethanol Formaldehyde Resin)

219 g of a 37% by mass of formalin aqueous solution (2.7 mol asformaldehyde, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and108.6 g of a 98% by mass of sulfuric acid (manufactured by MitsubishiGas Chemical Co., Ltd.) were placed in a 1 L-internal volume four-neckflask having an outlet at the bottom equipped with a Dimroth condenser,a thermometer and a stirring blade in a nitrogen gas flow. 94.8 g of amelted 1-naphthalenemethanol (0.6 mol, manufactured by Tokyo ChemicalIndustrial Co., Ltd.) was dropped thereto over 4 hours at normalpressure at about 100° C. under reflux and stirring, and thereafterallowed to react further for 2 hours. Then, 200 g of ethylbenzene(manufactured by Wako Pure Chemical Industry, Ltd.) and 150 g of methylisobutyl ketone (Wako Pure Chemical Industries, Ltd.) as dilutingsolvents were added thereto, and allowed to stand still; thereafter, anoil phase as a separated upper phase was left and a water phase as alower phase was removed. Further the oil phase was neutralized andwashed with water; and ethylbenzene and methyl isobutyl ketone weredistilled away under reduced pressure to thereby obtain 104.1 g of alight yellow solid naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 655; Mw was1,334; and Mw/Mn was 2.04. Further as a result of an organic elementalanalysis of the resin, the carbon content was 81.9% by mass; and theoxygen content was 12.0% by mass (the number of moles of oxygencontained per g of the resin was 0.0075 mol/g). Further the softeningpoint of the resin was 85° C.; and the hydroxyl value thereof was 40mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Example 4

(Naphthalenemethanol Formaldehyde Resin)

135 g of distilled water, 91 g of a 92% by mass of paraformaldehyde (2.8mol as formaldehyde, manufactured by Mitsubishi Gas Chemical Co., Ltd.),112 g of a 98% by mass of sulfuric acid (manufactured by Mitsubishi GasChemical Co., Ltd.), and 92 g of 1-butanol (1.2 mol, manufactured byWako Pure Chemical Industries, Ltd.) were placed in a 1 L-internalvolume four-neck flask having an outlet at the bottom equipped with aDimroth condenser, a thermometer and a stirring blade in a nitrogen gasflow. 98 g of a melted 1-naphthalenemethanol (0.6 mol, manufactured byTokyo Chemical Industrial Co., Ltd.) was dropped thereto over 5 hours atnormal pressure at about 100° C. under reflux and stirring, andthereafter allowed to react further for 2 hours. Then, 300 g ofethylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.) and150 g of methyl isobutyl ketone (Wako Pure Chemical Industries, Ltd.) asdiluting solvents were added thereto, and allowed to stand still;thereafter, an oil phase as a separated upper phase was left and a waterphase as a lower phase was removed. Further the oil phase wasneutralized and washed with water; and ethylbenzene and methyl isobutylketone were distilled away under reduced pressure to thereby obtain139.2 g of a light yellow liquid naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 380; Mw was473; and Mw/Mn was 1.25. Further as a result of an organic elementalanalysis of the resin, the carbon content was 78.3% by mass; and theoxygen content was 14.1% by mass (the number of moles of oxygencontained per g of the resin was 0.0088 mol/g). Further the hydroxylvalue of the resin was 43 mgKOH/g. Here, in the resin, nodinaphthylmethane was detected.

Example 5

(Naphthalenemethanol Formaldehyde Resin)

231 g of a 37% by mass of formalin aqueous solution (2.9 mol asformaldehyde, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and79.1 g of a 98% by mass of sulfuric acid (manufactured by Mitsubishi GasChemical Co., Ltd.) were placed in a 1 L-internal volume four-neck flaskhaving an outlet at the bottom equipped with a Dimroth condenser, athermometer and a stirring blade in a nitrogen gas flow; and 100 g of amelted 2-naphthalenemethanol (0.6 mol, manufactured by Wako PureChemical Industries, Ltd.) was dropped thereto over 4 hours at normalpressure at about 100° C. under reflux and stirring, and thereafterallowed to react further for 2 hours. Then, 150 g of ethylbenzene(manufactured by Wako Pure Chemical Industries, Ltd.) and 150 g ofmethyl isobutyl ketone (Wako Pure Chemical Industries, Ltd.) as dilutingsolvents were added thereto, and allowed to stand still; thereafter, anoil phase as a separated upper phase was left and a water phase as alower phase was removed. Further the oil phase was neutralized andwashed with water; and ethylbenzene and methyl isobutyl ketone weredistilled away under reduced pressure to thereby obtain 105.9 g of alight yellow solid naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 539; Mw was1,097; and Mw/Mn was 2.04. Further as a result of an organic elementalanalysis of the resin, the carbon content was 79.6% by mass; and theoxygen content was 14.3% by mass (the number of moles of oxygencontained per g of the resin was 0.0088 mol/g). Further the softeningpoint of the resin was 51° C.; and the hydroxyl value thereof was 45mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Example 6

(Modified Naphthalenemethanol Formaldehyde Resin)

100.0 g of the naphthalenemethanol formaldehyde resin (number of molesof oxygen contained: 0.75 mol) obtained in Example 3, and 106 g ofphenol (1.13 mol, manufactured by Wako Pure Chemical Industries, Ltd.)were placed in a 0.5 L-internal volume four-neck flask equipped with aLiebig condenser, a thermometer and a stirring blade in a nitrogen gasflow, and heated and melted at 100° C.; thereafter, 41 mg ofparatoluenesulfonic acid (manufactured by Wako Pure Chemical Industries,Ltd.) was added under stirring, and started to be allowed to react. Thereaction solution was heated up to 160° C., and allowed to react for 2hours. After the termination of the reaction, 360 g of a mixed solvent(metaxylene (Mitsubishi Gas Chemical Co., Ltd.)/methyl isobutyl ketone(Wako Pure Chemical Industries, Ltd.)=1/1 (mass ratio)) was addedthereto to dilute the reaction solution, which was then neutralized andwashed with water; and the solvent and the unreacted raw materials wereremoved under reduced pressure to thereby obtain 157 g of a blackishbrown modified naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 956; Mw was1,605; and Mw/Mn was 1.68. Further the hydroxyl value of the resin was277 mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Example 7

(Modified Naphthalenemethanol Formaldehyde Resin)

150.0 g of the naphthalenemethanol formaldehyde resin (number of molesof oxygen contained: 1.13 mol) obtained in Example 3, and 264 g ofphenol (2.82 mol, manufactured by Wako Pure Chemical Industries, Ltd.)were placed in a 1 L-internal volume four-neck flask equipped with aLiebig condenser, a thermometer and a stirring blade in a nitrogen gasflow, and heated and melted at 100° C.; thereafter, 41 mg ofparatoluenesulfonic acid (manufactured by Wako Pure Chemical Industries,Ltd.) was added under stirring, and started to be allowed to react. Thereaction solution was heated up to 155° C., and allowed to react for 2hours. After the termination of the reaction, 600 g of a mixed solvent(metaxylene (Mitsubishi Gas Chemical Co., Ltd.)/methyl isobutyl ketone(Wako Pure Chemical Industries, Ltd.)=1/1 (mass ratio)) was addedthereto to dilute the reaction solution, which was then neutralized andwashed with water; and the solvent and the unreacted raw materials wereremoved under reduced pressure to thereby obtain 255 g of a blackishbrown modified naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 670; Mw was881; and Mw/Mn was 1.32. Further the hydroxyl value of the resin was 298mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Example 8

(Modified Naphthalenemethanol Formaldehyde Resin)

55.0 g of the naphthalenemethanol formaldehyde resin (number of moles ofoxygen contained: 0.41 mol) obtained in Example 3, and 148.7 g of1-naphthol (1.03 mol, manufactured by Sugai Chemical Industry Co., Ltd.)were placed in a 0.5 L-internal volume four-neck flask equipped with aLiebig condenser, a thermometer and a stirring blade in a nitrogen gasflow, and heated and melted at 100° C.; thereafter, 61 mg ofparatoluenesulfonic acid (manufactured by Wako Pure Chemical Industries,Ltd.) was added under stirring, and started to be allowed to react. Thereaction solution was heated up to 175° C., and allowed to react for 2.5hours. After the termination of the reaction, 300 g of a mixed solvent(metaxylene (Mitsubishi Gas Chemical Co., Ltd.)/methyl isobutyl ketone(Wako Pure Chemical Industries, Ltd.)=1/1 (mass ratio)) was addedthereto to dilute the reaction solution, which was then neutralized andwashed with water; and the solvent and the unreacted raw materials wereremoved under reduced pressure to thereby obtain 122 g of a blackishbrown modified naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 571; Mw was712; and Mw/Mn was 1.25. Further the hydroxyl value of the resin was 246mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Example 9

(Modified Naphthalenemethanol Formaldehyde Resin)

100.0 g of the naphthalenemethanol formaldehyde resin (number of molesof oxygen contained: 0.88 mol) obtained in Example 4, and 207 g ofphenol (2.2 mol, manufactured by Wako Pure Chemical Industries, Ltd.)were placed in a 1 L-internal volume four-neck flask equipped with aLiebig condenser, a thermometer and a stirring blade in a nitrogen gasflow, and heated and melted at 100° C.; thereafter, 41 mg ofparatoluenesulfonic acid (manufactured by Wako Pure Chemical Industries,Ltd.) was added under stirring, and started to be allowed to react. Thereaction solution was heated up to 160° C., and allowed to react for 2hours. After the termination of the reaction, 350 g of a mixed solvent(metaxylene (Mitsubishi Gas Chemical Co., Ltd.)/methyl isobutyl ketone(Wako Pure Chemical Industries, Ltd.)=1/1 (mass ratio)) was addedthereto to dilute the reaction solution, which was then neutralized andwashed with water; and the solvent and the unreacted raw materials wereremoved under reduced pressure to thereby obtain 151 g of a blackishbrown modified naphthalenemethanol formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 537; Mw was653; and Mw/Mn was 1.22. Further the hydroxyl value of the resin was 340mgKOH/g. Here, in the resin, no dinaphthylmethane was detected.

Comparative Example 1

(Naphthalene Formaldehyde Resin)

703.0 g of a 47% by mass of formalin aqueous solution (11.0 mol asformaldehyde, manufactured by Mitsubishi Gas Chemical Co., Ltd.), 240.0g of a 98% by mass of sulfuric acid (3.6 mol, manufactured by KantoChemical Co., Ltd.), 467.0 g of naphthalene (manufactured by Wako PureChemical Industries, Ltd.), and 100 g of n-octane (manufactured by WakoPure Chemical Industries, Ltd.) were successively placed in a 2L-internal volume four-neck flask having an outlet at the bottomequipped with a Dimroth condenser, a thermometer and a stirring blade ina nitrogen gas flow. The reaction solution was allowed to react atnormal pressure at about 100° C. for 6 hours under reflux and stirringat a rotation frequency of 200 rpm. Then, the reaction solution wasallowed to stand still; thereafter, an oil phase as a separated upperphase was left and a water phase as a lower phase was removed. Furtherthe oil phase was two times washed with warm water, and subjected to apressure-reduction treatment at 150° C./30 mmHg for 1 hour to therebyobtain 460.0 g of a light yellow naphthalene formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 293; Mw was530; and Mw/Mn was 1.81. Further as a result of an organic elementalanalysis of the resin, the carbon content was 83.8% by mass; and theoxygen content was 10.0% by mass. Here, in the resin, the presence ratioof dinaphthylmethane was 2%.

Comparative Example 2

(Modified Naphthalene Formaldehyde Resin)

100 g of the resin obtained in Comparative Example 1, and 220.0 g ofphenol (2.34 mol, manufactured by Tokyo Chemical Industry Co., Ltd.)were placed in a 1.0 L-internal volume four-neck flask equipped with aLiebig condenser, a thermometer and a stirring blade in a nitrogen gasflow, and heated and melted at 120° C.; thereafter, 34.4 mg ofparatoluenesulfonic acid (manufactured by Wako Pure chemical Industries,Ltd.) was added under stirring to start to be allowed to react. Thereaction solution was immediately heated up to 190° C., and stirred for3 hours; thereafter, 500 g of a mixed solvent (metaxylene (MitsubishiGas Chemical Co., Ltd.)/methyl isobutyl ketone (Kanto Chemical Co.,Ltd.)=1/1 (mass ratio)) was added thereto to dilute the reactionsolution, which was then neutralized and washed with water; and thesolvent was removed under reduced pressure to thereby obtain 135.0 g ofa blackish brown modified dimethylnaphthalene formaldehyde resin.

As a result of GPC analysis of the obtained resin, Mn was 430; Mw was675; and Mw/Mn was 1.57. Further the hydroxyl value of the resin was 279mgKOH/g. Here, in the resin, the presence ratio of dinaphthylmethane was1.5%.

A biphenyl-based epoxy resin (manufactured by Nippon Kayaku Co., Ltd.,product name: “NC-3000”) was used as an epoxy resin; the modifiednaphthalenemethanol formaldehyde resin obtained in Example 6 was used asa curing agent; and triphenylphosphine was used as a curing accelerator,and these were mixed in a blend ratio shown in Table 1, and formed whilecuring at 220° C. for 70 minutes to thereby obtain a cured test piece.The cured test piece was tested for the thermogravimetric loss rate. Theresult is shown in Table 1.

A biphenyl-based epoxy resin (manufactured by Nippon Kayaku Co., Ltd.,product name: “NC-3000”) was used as an epoxy resin; the modifiednaphthalene formaldehyde resin obtained in Comparative Example 2 wasused as a curing agent; and triphenylphosphine was used as a curingaccelerator, and these were mixed in a blend ratio shown in Table 1, andformed while curing at 220° C. for 70 minutes to thereby obtain a curedtest piece. The cured test piece was tested for the thermogravimetricloss rate. The result is shown in Table 1.

TABLE 1 Comparative Example 6 Example 2 Blending biphenyl-based epoxyresin 50 50 (parts by mass) curing agent (parts by mass) 50 50triphenylphosphine (parts by mass) 1.0 1.0 Thermogravimetric Loss Rate(% by mass) 0.6 6.6

Epoxy Resin Example 10

(Naphthalene-Based Epoxy Resin)

150.0 g of the modified naphthalenemethanol formaldehyde resin obtainedin Example 6, 434.0 g of epichlorohydrin, and 170.0 g of isopropylalcohol were placed in a 2 L-internal volume four-neck flask equippedwith a cooling tube, a thermometer and a stirring device, and heated to40° C. to be homogeneously dissolved; and thereafter, 74 g of a 48.5% bymass of sodium hydroxide aqueous solution was dropped therein over 60minutes. During that, the temperature of the system was gradually raisedso that the temperature in the system arrives at 65° C. after thetermination of the dropping. Thereafter, the temperature was held at 65°C. for 30 minutes and the reaction was completed; then, by-producedsalts and excessive sodium hydroxide were removed by washing with water.Then, excessive epichlorohydrin and isopropyl alcohol were distilledaway under reduced pressure from the reaction product to thereby obtaina crude epoxy resin. The crude epoxy resin was dissolved in 300 g ofmethyl isobutyl ketone; 5 g of a 48.5% by mass of sodium hydroxideaqueous solution was added and allowed to react at 65° C. for 1 hour.Thereafter, a sodium phosphate aqueous solution was added to thereaction solution to neutralize excessive sodium hydroxide, andby-produced salts were removed by washing with water. Then, methylisobutyl ketone was completely removed under reduced pressure to therebyobtain 160 g of an epoxy resin as a target. The epoxy equivalent of theobtained epoxy resin was 290 g/eq, and the content of the hydrolyzablehalogen was 500 ppm.

Example 11

(Naphthalene-Based Epoxy Resin)

150.0 g of the modified naphthalenemethanol formaldehyde resin obtainedin Example 9, 434.0 g of epichlorohydrin, and 170.0 g of isopropylalcohol were placed in a 2 L-internal volume four-neck flask equippedwith a cooling tube, a thermometer and a stirring device, and heated to40° C. to be homogeneously dissolved; and thereafter, 74 g of a 48.5% bymass of sodium hydroxide aqueous solution was dropped therein over 60minutes. During that, the temperature of the system was gradually raisedso that the temperature in the system arrives at 65° C. after thetermination of the dropping. Thereafter, the temperature was held at 65°C. for 30 minutes and the reaction was completed; then, by-producedsalts and excessive sodium hydroxide were removed by washing with water.Then, excessive epichlorohydrin and isopropyl alcohol were distilledaway under reduced pressure from the reaction product to thereby obtaina crude epoxy resin. The crude epoxy resin was dissolved in 300 g ofmethyl isobutyl ketone; 5 g of a 48.5% by mass of sodium hydroxideaqueous solution was added and allowed to react at 65° C. for 1 hour.Thereafter, a sodium phosphate aqueous solution was added to thereaction solution to neutralize excessive sodium hydroxide, andby-produced salts were removed by washing with water. Then, methylisobutyl ketone was completely removed under reduced pressure to therebyobtain 155 g of an epoxy resin as a target. The epoxy equivalent of theobtained epoxy resin was 277 g/eq, and the content of the hydrolyzablehalogen was 550 ppm.

From the above results, it is clear that the aromatic hydrocarbonformaldehyde resin obtained in the present embodiment contained moresufficiently decreased diarylmethanes being nonreactive dimers thanconventionally. It is further clear that the modified aromatichydrocarbon formaldehyde resin obtained by using the aromatichydrocarbon formaldehyde resin as a raw material was better in thethermal decomposition resistance and contained more sufficientlydecreased diarylmethanes being nonreactive dimers than modifiednaphthalene formaldehyde resins synthesized by conventional methods.

The present application is based on the Japanese Patent Application(Japanese Patent Application No. 2013-127437), filed on Jun. 18, 2013,the entire contents of which are incorporated hereby by reference.

INDUSTRIAL APPLICABILITY

The aromatic hydrocarbon formaldehyde resin, the modified aromatichydrocarbon formaldehyde resin and the epoxy resin according to thepresent invention can be utilized in broad applications includingelectric insulating materials, resist resins, semiconductor sealingresins, printed wiring board adhesives, matrix resins for electriclaminated plates mounted on electric devices, electronic devices,industrial devices and the like, build-up laminated plate materials,fiber-reinforced plastic resins, sealing resins for liquid crystaldisplay panels, coating materials, various types of coating agents,adhesives, coating agents for semiconductors and resist resins in thesemiconductor production.

The invention claimed is:
 1. An aromatic hydrocarbon formaldehyde resin,being obtained by reacting an aromatic hydrocarbon compound (A)represented by the following formula (1) with formaldehyde (B) in thepresence of an acidic catalyst:

wherein R represents an organic group having 1 to 10 carbon atoms; 1represents an integer of 0 to 2, and m and n represent integerssatisfying 1≦m+n≦10, m≧0 and n≧1, said aromatic hydrocarbon formaldehyderesin comprising substantially no diarylmethane.
 2. The aromatichydrocarbon formaldehyde resin according to claim 1, being obtained byreacting the aromatic hydrocarbon compound (A) with formaldehyde (B) ina molar ratio of (A):(B)=1:1 to 1:20 in the presence of an acidiccatalyst.
 3. The aromatic hydrocarbon formaldehyde resin according toclaim 1, wherein the reaction of the aromatic hydrocarbon compound (A)with formaldehyde (B) is carried out in the presence of an alcohol. 4.The aromatic hydrocarbon formaldehyde resin according to claim 1, havinga weight-average molecular weight of 200 to 25,000.
 5. The aromatichydrocarbon formaldehyde resin according to claim 1, having an oxygencontent of 7 to 18% by mass.
 6. A method for producing an aromatichydrocarbon formaldehyde resin, comprising reacting an aromatichydrocarbon compound (A) represented by the following formula (1) withformaldehyde (B) in the presence of an acidic catalyst:

wherein R represents an organic group having 1 to 10 carbon atoms; 1represents an integer of 0 to 2, and m and n represent integerssatisfying 1≦m+n≦10, m≧0 and n≧1 to produce an aromatic hydrocarbonformaldehyde resin comprising substantially no diarylmethane.
 7. Amodified aromatic hydrocarbon formaldehyde resin, being obtained byreacting an aromatic hydrocarbon formaldehyde resin according to claim 1with at least one selected from the group consisting of compoundsrepresented by the following formulae (2) and (3) in the presence of anacidic catalyst:

wherein X and Y each independently represent a hydrogen atom or anorganic group having 1 to 10 carbon atoms; and a and b representintegers satisfying 1≦a+b≦10, a≧1 and b≧0, and c represents an integerof 0 to
 2. 8. The modified aromatic hydrocarbon formaldehyde resinaccording to claim 7, wherein the compounds represented by the formulae(2) and (3) are at least one selected from the group consisting ofphenol, cresol, catechol, hydroquinone, phenylphenol, biphenol,naphthol, dihydroxynaphthalene, hydroxyanthracene anddihydroxyanthracene.
 9. A method for producing a modified aromatichydrocarbon formaldehyde resin, comprising reacting an aromatichydrocarbon formaldehyde resin according to claim 1 with at least oneselected from the group consisting of compounds represented by thefollowing formulae (2) and (3) in the presence of an acidic catalyst:

wherein X and Y each independently represent a hydrogen atom or anorganic group having 1 to 10 carbon atoms; and a and b representintegers satisfying 1≦a+b≦10, a≧1 and b≧0, and c represents an integerof 0 to
 2. 10. An epoxy resin, being obtained by reacting a modifiedaromatic hydrocarbon formaldehyde resin according to claim 7 withepichlorohydrin.
 11. A method for producing an epoxy resin, comprisingreacting a modified aromatic hydrocarbon formaldehyde resin according toclaim 7 with epichlorohydrin to thereby obtain the epoxy resin.
 12. Thearomatic hydrocarbon formaldehyde resin according to claim 2, whereinthe reaction of the aromatic hydrocarbon compound (A) with formaldehyde(B) is carried out in the presence of an alcohol.
 13. The aromatichydrocarbon formaldehyde resin according to claim 2, having aweight-average molecular weight of 200 to 25,000.
 14. The aromatichydrocarbon formaldehyde resin according to claim 2, having an oxygencontent of 7 to 18% by mass.
 15. The aromatic hydrocarbon formaldehyderesin according to claim 2, comprising substantially no diarylmethane.16. A modified aromatic hydrocarbon formaldehyde resin, being obtainedby reacting an aromatic hydrocarbon formaldehyde resin according toclaim 2 with at least one selected from the group consisting ofcompounds represented by the following formulae (2) and (3) in thepresence of an acidic catalyst:

wherein X and Y each independently represent a hydrogen atom or anorganic group having 1 to 10 carbon atoms; and a and b representintegers satisfying 1≦a+b≦10, a≧1 and b≧0, and c represents an integerof 0 to
 2. 17. The aromatic hydrocarbon formaldehyde resin according toclaim 2, having a weight-average molecular weight of 200 to 25,000. 18.The aromatic hydrocarbon formaldehyde resin according to claim 2, havingan oxygen content of 7 to 18% by mass.
 19. The aromatic hydrocarbonformaldehyde resin according to claim 2, comprising substantially nodiarylmethane.